Many portable electronic devices include displays for displaying various types of images. Examples of such displays include electrowetting displays (EWDs), liquid crystal displays (LCDs), electrophoretic displays (EPDs), light emitting diode displays (LED displays), etc. In EWD applications, an addressing scheme is utilized to drive the pixels of the EWD. Generally, one of the points of emphasis for EWD applications is low power design since in today's applications, EWDs are intended to be used in mobile and portable media devices.
An input video-stream generally represents a sequence of pixels, grouped per line; a sequence of lines, grouped per frame; and a sequence of frames defining a moving video stream (movie). When such a video stream is to be reproduced on an active matrix EWD, a timing controller and display drivers are used to transfer the video data towards the actual pixels of the EWD. A specific addressing scheme is used by the timing controller to timely control row and column drivers of the EWD. The purpose of an addressing scheme is to set (or maintain) the state of a pixel. The addressing scheme drives an active matrix transistor array and provides analog voltages to individual sub-pixels of the EWD. These voltages modulate the luminance transmission and/or reflectivity of the sub-pixels of the EWD. The sub-pixels are grouped per row and when a row is addressed, voltages of a complete row are stored as charge on corresponding sub-pixel capacitors. As the video-data is repeatedly updated, still and moving images can be reproduced by the EWD.
Each address cycle consumes an amount of energy. Furthermore, leakage of the sub-pixel capacitors (e.g. current through active matrix switches and dielectric materials) causes a degrading transmission/reflectivity. Additionally, backflow of in electrowetting liquids of the EWD is another cause of degrading transmission/reflectivity. Reset pulses used in EWDs also cause a temporary reduction of transmission/reflectivity. The temporary reduction of transmission/reflectivity causes visual image artifacts.